【国外标准】 Standard Test Method for Determination of Trace Elements in Biodiesel and Biodiesel Blends by Microwave Plasma Atomic Emission Spectrometry (MP-AES)

5.1 This test method covers the determination of five elements (Ca, Mg, K, Na, and P) in biodiesel and biodiesel blends.5.2 The presence of metals and metalloids in engine fuels can influence the performance of engines and contribute to shortening the lifetime of the equipment. In addition, some elements act as catalyst poison contributing to increases in the amount of unwanted gases and particulate matter emitted by vehicles.1.1 This test method covers the determination of elements in biodiesel and biodiesel blends by microwave plasma atomic emission spectrometry (MP-AES). The specific elements within the scope of this method are calcium (Ca), magnesium (Mg), phosphorus (P), potassium (K), and sodium (Na).1.2 This test method conforms to Practice D6300, subection 8.4.5, valid test result range, and subsection 8.4.6, working range specifications. The valid test result range and working range are recent additions to Practice D6300, and a graphical representation using example values is shown in Appendix X2, Test Method Operating Range.1.3 Method working range:high expected concentration limit = highest ILS sample meanlow expected concentration limit = lowest ILS sample mean if:     lowest ILS sample mean − Rlowest ILS sample mean > 0; otherwise it is     determined by solving for X using the following equation:     X − RX = coarsest resolution, determined by 0.5*σr lowest ILS sample meanBiodiesel and Biodiesel BlendsElement Method Working Range(expected mg/kg)Calcium 0.24 to 15.01Magnesium 0.12 to 11.55Phosphorus 1.69 to 14.24Potassium 0.49 to 13.98Sodium 0.90 to 14.301.4 This test method uses organic elemental standards in organic solvents for calibration and does not purport to quantitatively determine insoluble particulates. Analytical results are particle size dependent, and particles larger than a few micrometers can cause results to appear low.1.5 Elements present at mass fractions above the upper limit of the calibration curves can be determined with additional appropriate dilutions. Elements shall be measured at the wavelengths presented in Table 1. Alternate wavelengths noted in Appendix X1 may be used in the rare case of spectral interference.1.6 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.1.7 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.1.8 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.